The present invention relates generally to surgical instruments, and more particularly to surgical clips and instruments for applying or placing such surgical clips.
A wide number of surgical procedures employ surgical clips of a variety of configurations to provide, for example, hemostasis and occlusion of anatomical structures (i.e., tissue, blood vessels or other fluid ducts) or to secure the ends of a suture, as in place of a conventional suture knot. Often it is required to efficiently place a number of surgical clips during a single surgical procedure.
Surgical clips are commonly used to ligate, clamp, close off or otherwise occlude blood vessels in a surgical site to keep the surgical site free of blood and minimize blood loss from the patient. For example, when the surgery involves the removal of a portion of the body, such as an organ, graft vessel, tumor, or the like, that portion must be first separated from the attached vessels. In these types of procedures a vessel is ligated by action of one or more surgical clips placed at a desired location and is then severed downstream of the ligated location. In some instances, it may be desirable to place one or more clips at two adjacent locations and then sever the vessel in between the locations of the clips.
The clips are often in the form of thin, narrow, metal or polymeric U-shaped or V-shaped members that are placed over the vessel, tissue or suture material and then forced into a closed positioning using a clip applicator constructed for such purpose. The clips, typically constructed of metal, may be initially open and then permanently deformed into a closed or clamped configuration around the desired blood vessel or other tissue structure using an appropriate clip applicator. Examples of such clips are described in U.S. Pat. Nos. 5,201,746; 4,976,722; 4,844,066; 4,799,481; 4,449,530; and 4,146,130.
In many instances, and particularly when the clip is constructed of a material other than metal, the clip will include a latch feature to ensure that the clip remains closed with sufficient force to provide full and complete hemostasis or occlusion and to ensure that the clip will not loosen or open over time. Such latched clips are described, for example, in U.S. Pat. Nos. 5,160,339; 4,620,541, and 4,579,118.
Clips that have clamping members formed in a normally closed position are also known. Normally closed clips typically have their clamping members biased together by way of the elasticity of the material from which it is constructed. In general, to apply a clip configured in a normally closed position, the clamping members must be forced open by an appropriate clip applicator and then released to its closed position in place over the desired structure to be clamped. Normally closed clips may be formed of a continuous wire having torsion spring or tension coil as described, for example, in U.S. Pat. No. 5,593,414 or may be of a variety of other configurations such as, for example, those described in U.S. Pat. Nos. 5,695,505; 5,601,574; 5,366,458; and 4,957,500.
Whether the clip is configured in a normally closed or normally open configuration, the clip must provide sufficient clamping force to secure the structure being clamped. In the case of ligating blood vessels or the like, the clips must provide sufficient clamping force to fully close the vessel to ensure complete hemostasis. In addition, to prevent leakage or positional migration, the clips must remain tightly closed in their clamped position without any significant loosening or relaxing over time.
These requirements tend to result in the necessity for the clip to deliver a substantial amount of force to the structure to be clamped. In turn, the clip applier apparatuses for applying these clips must proportionally provide sufficiently high forces to either deform the clamp to its closed position or force the clamp to an open position for delivery. As a result, known clip appliers have been characterized by relatively complicated and bulky jaw assemblies designed to generate the high forces required to reliably and permanently apply the clips.
The complication and bulkiness associated with the clip applicators have a number of adverse effects. The added size or bulk of the clip applier adversely affects the ability of the surgeon to view the clip that is about to be applied. In many cases, the clip is almost completely obscured from view by the jaw assembly that is required to open or close the clamp. Further, excessive forces required to open or close the surgical clip must ultimately be delivered by the hand of the surgeon, often in the context of very delicate and precise surgical manipulations.
In endoscopic surgical procedures, where the clips must be delivered and applied to a surgical site through the small diametrical operating space of a relatively long cannula, these deficiencies become even more acute. Excessively large clip applicator mechanisms are inappropriate for endoscopic delivery and tend to adversely affect the endoscopic visibility of the clip placement at the surgical site. Further, in an endoscopic procedure, even small movements at the proximal end of a clip applier device may be greatly magnified at the distal end which is located a relatively large distance away at the surgical site. Accordingly, excessive forces required to apply a surgical clip tend to adversely effect the precision with which a clip may be delivered.
In view of these and other prevalent problems of known clips and clip appliers it would be desirable to have a reliable surgical clip configured for placement using only minimal force. It would be further desirable to have a surgical clip that allows improved visual access to its clamping members during placement and closure around a structure to be clamped. Further, it would be desirable to have a clip applier apparatus that can surgically apply the clips to the desired structure without substantial visual obstruction to the clamping portion of the clip. Most desirably, the clip and clip applier apparatus would operate in conjunction to allow the clip applier to be loaded with a number of clips for sequential delivery of one or more clips at a time.
The present invention involves a surgical clip for clamping or grasping a target structure and having a pair of opposing clamp arms held together in a normally closed relationship by a connecting member. The clamp arms of the surgical clip may be forced open and conveniently held open for placement over a desired structure. In one aspect of the present invention, the clamp arms are held open by a secondary member or locking mechanism. In that case, the clamp arms are released by displacing the secondary member or actuating the locking mechanism. In another aspect of the present invention, the clamp arms are opened or held open by a clip applicator.
In a preferred embodiment, the surgical clip has a first clamp arm and a second clamp arm, each clamp arm having an associated clamping surface. A connecting portion extends between and connects the clamp arms, biasing the clamping surfaces to a substantially parallel and closed relationship. In the closed position, the clamping surfaces may be in direct contact with each other or may be spaced apart a desired distance. The clamp arms are movable to an open position wherein the clamping surfaces are disposed in an angular relationship.
In one aspect of the present invention, the clamp arms and associated clamping surfaces are held open by a device, member, or mechanism or the like disposed between the clamp arms at a position away from the distal ends of the clamp arms. Preferably, the clamp arms are held open at a proximal location along the length of the clamp arms, most preferably near the apex of the angle between the clamping surfaces.
The clamp arms may have opposing surfaces located near the apex of the angle between the clamping surfaces and adapted to receive a secondary member to hold the clamp arms in the opened position. The opposing surfaces may be relatively short compared to the length of the clamping arms, preferably less than about 25% of the length of the clamp arms. In a preferred embodiment, the opposing surfaces are substantially parallel when the clip is in the opened position and spaced apart a distance of between about 0.01 inches (0.25 mm) to about 0.05 inches (1.27 mm).
In one embodiment of the present invention, a secondary member is disposed between the opposing surfaces to hold or lock the clamp arms in the opened position. The secondary member may be a pin or ring-like element having a cross-sectional dimension selected to substantially match the distance between the opposing surfaces when the clamp arms are in the opened position. The opposing surfaces may further include a detent to cooperate with the secondary member.
In one embodiment, the connecting portion includes an opening with the opposing surfaces terminating proximally within the opening. This arrangement of the opening provides clearance for the secondary member once displaced in the proximal direction from between the opposing surfaces, thus allowing the clamp arms to close. Accordingly, the opening is preferably configured to be at least as large as the cross-section of the secondary member so as to allow the clamp arms to close without obstruction. In one preferred embodiment, the connecting portion has a channel extending across its width to provide further clearance of a secondary member or to facilitate removal of a secondary member. The depth of the channel is preferably about 75% or less of the thickness of the connecting portion.
The connecting portion may have any number of orientations relative to the plane of the clamp arms. The clamp arms and connecting portion may be substantially in a common plane, that is, the surgical clip is relatively flat. In other embodiments, the clamp arms may lie in a plane which is parallel and offset from the plane of the connecting portion.
The present invention also involves a surgical clip assembly for clamping a target structure. The surgical clip assembly generally includes a normally closed surgical clip having clamp arms and a secondary member positioned between the clamp arms holding the clamp arms in an opened position.
In a preferred embodiment, the surgical clip has a pair of opposing clamp arms, each clamp arm having an associated clamping surface, and an connecting portion extending therebetween and biasing the clamping surfaces in a substantially closed relationship for clamping a target structure. The clamp arms are moveable to an open position wherein the clamping surfaces are disposed in an angular relationship. The clamp arms preferably have opposing surfaces near the apex of the angle.
The secondary member is preferably positioned between said opposing surfaces to hold the clamping surfaces in the opened position, preventing the clamping surfaces from returning to the substantially closed relationship. The secondary member may be a pin, a ring-like member, or a substantially closed ring. The cross-section of the secondary member may be generally round or substantially square, in any case having a cross-sectional dimension selected to hold the clamping surfaces in the desired open position. In a preferred embodiment, at least a portion of the secondary member is substantially planar to the plane of the clamp arms.
The present invention also involves a method of applying a surgical clip to a target structure using a clip applicator. The method may preferably include the steps of (a) providing a surgical clip having a pair of opposing clamp arms movable between a normally closed position and an open position for receiving a target structure between the clamp arms; (b) forcing the clamp arms from the normally closed position to the open position; (c) locking the clamp arms in the open position; (d) loading the opened surgical clip into a surgical clip delivery device; (e) positioning the target structure between the opened clamp arms; and (f) unlocking the clamp arms, whereby the clamp arms return to the normally closed clamping position over the target structure.
The present invention also involves a method of applying a surgical clip to a target structure. The method preferably includes the steps of: (a) providing a surgical clip having a pair of opposing clamp arms joined at a proximal end and being moveable between a normally closed clamping position and an open position for receiving the target structure; (b) forcing the clamp arms from the normally closed clamping position to the open position; (c) positioning a secondary member at a proximal position between the opposing clamp arms, the secondary member preventing the clamp arms from returning to the closed position; (d) positioning the target structure between the opened clamp arms; and (e) displacing the secondary member from the proximal position, whereby the opposing clamp arms are allowed to close upon the target structure. The method may further involve the steps of (f) displacing the secondary member to a position within a clearance hole provided immediately proximal to the proximal position of the secondary member; and (g) removing the secondary member from the clearance hole.
In one embodiment, the step of forcing the clamp arms from the normally closed position to the open position comprises the steps of providing a stationary pin at a distal location relative to the clamp arms, moving the surgical clip towards the pin until the pin engages and begins to spread the clamp arms, and advancing the clip relative to the pin until the pin is at the proximal position and the clamp is opened. Preferably, the pin is oriented substantially transverse or perpendicular to the plane of the clamp arms.
The present invention also involves a clip applicator for delivering a surgical clip assembly having a surgical clip and a secondary member holding the surgical clip in an opened position. The secondary member is preferably a pin or ring, at least a portion of which is relatively perpendicular to the plane of the surgical clip. According to one aspect of the present invention, the clip applicator holds the secondary member in a fixed position and urges or advances the surgical clip relative to the secondary member to displace the surgical clip from the secondary member, thus allowing the surgical clip to close.
In one embodiment, the clip applicator has a shaft member having a distal slot for receiving the body of the clip and one or more additional features (i.e., hooks, slots, etc.) for holding or capturing the secondary member, which preferably is positioned at a proximal position between the clamp arms; The shaft member may have a slidable rod disposed within a central lumen, the distal end of the rod adapted to engage the surgical clip and urge it in a distal direction to displace it from the secondary member. The secondary member may be a pin or ring or the like having a cross-sectional dimension selected to hold the surgical clip in the desired open condition.
The present invention also involves a clip applicator for delivering a surgical clip to having an elastic connecting portion which, when compressed, opens the clamp arms. The clip applicator generally has a delivery tube having a central lumen for receiving one or more surgical clips. At least a portion of the central lumen is sized and dimensioned to hold the connecting portion in a compressed state, thereby holding the clamp arms in an open position. When the connecting portion of the surgical clip is advanced beyond the distal end of the central lumen, the connecting portion is allowed to return to its uncompressed state, thus closing the clamp arms. A number of surgical clips may be sequentially advanced through the central lumen.